Study on the regulation of resin carbon distribution based on water-alcohol system and its effect on the toughness of carbon paper

Carbon paper is widely used in the gas diffusion layer of proton exchange membrane fuel cell because of its good mechanical strength, electrical conductivity and dimensional stability. However, brittleness has become a major challenge in its application. In this study, binary mixed solution was used as the diluent of alcohol-soluble phenolic resin to improve the fracture toughness and air permeability of carbon paper. It is found that alcohol-soluble phenolic resin can stably exist in aqueous alcohol solution with anhydrous ethanol volume fraction of not less than 60%. In the impregnation system with different volume fractions of anhydrous ethanol, the distribution form of resin carbon can be effectively regulated, so that the resin carbon is mainly distributed in the lap position of carbon fiber in the form of blocks rather than flakes, which not only ensures the good adhesion of chopped carbon fiber, but also improves the toughness and air permeability of carbon paper.. The results show that the carbon paper prepared in the impregnation system with 60% anhydrous ethanol has higher tensile strength (9.9 MPa), higher fracture toughness (7.6 MJ/m 3 ) and better air permeability (1.39×105 mL·mm/ ( cm 2 ·h·mmHg)). This work provides a reference for the regulation of resin—carbon distribution and the toughness enhancement of carbon paper.